The study of the gene and its product using immunochemical and immunogenetic principles and technics. Major emphasis on using about 20 different immunogenetic parameters to study the evolution and phylogenetics of cattle breeds for use in the rational development of future breeding and preservation programs; the study of blood groups and inherited type-specific serum proteins (immunoglobulin allotypes) in cattle, monkeys, and birds, and the production of artificial chimeras to assay for somatic cell mating of hematopoietic tissues. The various immunogenetic parameters are used to study the development (ontogeny) of antigens, maternal-fetal interactions such as hemolytic disease of the newborn, and histocompatibility. Computer programs are used extensively for data storage and analysis.